By Veronique Greenwood You might mistake jewel wings for their colorful cousins, dragonflies. New research shows that these two predators share something more profound than their appearance, however. In a paper published this month in Current Biology, Dr. Gonzalez-Bellido and colleagues reveal that the neural systems behind jewel wings’ vision are shared with dragonflies, with whom they have a common ancestor that lived before the dinosaurs. But over the eons, this brain wiring has adapted itself in different ways in each creature, enabling radically different hunting strategies. For flying creatures, instantaneous, highly accurate vision is crucial to survival. Recent research showed that birds of prey that fly faster also see changes in their field of vision more quickly, demonstrating the link between speed on the wing and speed in the brain. But the group of insects that includes jewel wings and dragonflies took to the air long before birds were even on the evolutionary horizon, and their vision is swifter than any vertebrate’s studied thus far, said Dr. Gonzalez-Bellido. Researchers looking to understand how their vision, flight and hunting abilities are connected are thus particularly interested in the neurons that send visual information to the wings. But recordings made in the lab by Dr. Gonzalez-Bellido and her colleagues confirmed that dragonflies rise up in a straight line to seize unsuspecting insects from below, almost like their prey had stepped on a land mine. This eerie climb may contribute to their startling success rate: Dragonflies snag their prey 97 percent of the time. The difference in hunting behavior may be linked to the placement of the insects’ eyes. Jewel wings’ eyes are on either side of the head, facing forward. The eyes of these dragonflies — the species Sympetrum vulgatum, also known as the vagrant darter — encase the top of the insect’s head in an iridescent dome, with a thin line running down the middle the only visible reminder that they may have once been separate. © 2020 The New York Times Company

Keyword: Vision; Evolution
Link ID: 27008 - Posted: 01.29.2020

Jordana Cepelewicz Part of the brain’s allure for scientists is that it is so deeply personal — arguably the core of who we are and what makes us human. But that fact also renders a large share of imaginable experiments on it monstrous, no matter how well intended. Neuroscientists have often had to swallow their frustration and settle for studying the brains of experimental animals or isolated human neurons kept alive in flat dishes — substitutes that come with their own ethical, practical and conceptual limitations. A new world of possibilities opened in 2008, however, when researchers learned how to create cerebral organoids — tiny blobs grown from human stem cells that self-organize into brainlike structures with electrically active neurons. Though no bigger than a pea, organoids hold enormous promise for improving our understanding of the brain: They can replicate aspects of human development and disease once thought impossible to observe in the laboratory. Scientists have already used organoids to make discoveries about schizophrenia, autism spectrum disorders and the microcephaly caused by the Zika virus. Yet the study of brain organoids can also be fraught with ethical dilemmas. “In order for it to be a good model, you want it to be as human as possible,” said Hank Greely, a law professor at Stanford University who specializes in ethical and legal issues in the biosciences. “But the more human it gets, the more you’re backing into the same sorts of ethics questions that are the reasons why you can’t just use living humans.” In the popular imagination, fueled by over-the-top descriptions of organoids as “mini-brains,” these questions often center on whether the tissue might become conscious and experience its unnatural existence as torture. The more immediate, realistic concerns that trouble experts are less sensational but still significant. It also doesn’t help that the study of organoids falls into an odd gap between other areas of research, complicating formal ethical oversight. Still, no one wants to see brain organoids’ potential discarded lightly. All Rights Reserved © 2020

Keyword: Development of the Brain
Link ID: 27007 - Posted: 01.29.2020

By Theodor Schaarschmidt A 51-year-old man I will call “Mr. Pinocchio” had a strange problem. When he tried to tell a lie, he often passed out and had convulsions. In essence, he became a kind of Pinocchio, the fictional puppet whose nose grew with every fib. For the patient, the consequences were all too real: he was a high-ranking official in the European Economic Community (since replaced by the European Union), and his negotiating partners could tell immediately when he was bending the truth. His condition, a symptom of a rare form of epilepsy, was not only dangerous, it was bad for his career. Doctors at the University Hospitals of Strasbourg in France discovered that the root of the problem was a tumor about the size of a walnut. The tumor was probably increasing the excitability of a brain region involved in emotions; when Mr. Pinocchio lied, this excitability caused a structure called the amygdala to trigger seizures. Once the tumor was removed, the fits stopped, and he was able to resume his duties. The doctors, who described the case in 1993, dubbed the condition the “Pinocchio syndrome.” Mr. Pinocchio’s plight demonstrates the far-reaching consequences of even minor changes in the structure of the brain. But perhaps just as important, it shows that lying is a major component of the human behavioral repertoire; without it, we would have a hard time coping. When people speak unvarnished truth all the time—as can happen when Parkinson’s disease or certain injuries to the brain’s frontal lobe disrupt people’s ability to lie—they tend to be judged tactless and hurtful. In everyday life, we tell little white lies all the time, if only out of politeness: Your homemade pie is awesome (it’s awful). No, Grandma, you’re not interrupting anything (she is). A little bit of pretense seems to smooth out human relationships without doing lasting harm. © 2020 Scientific American

Keyword: Emotions
Link ID: 27006 - Posted: 01.29.2020

Rhitu Chatterjee One in seven women experiences depression during or after pregnancy. The good news is that perinatal depression is treatable. Here are five things to know about perinatal depression, its symptoms and treatment options. Loveis Wise for NPR Shortly after she gave birth to her son last May, Meghan Reddick, 36, began to struggle with depression. "The second I had a chance where I wasn't holding [my son], I would go to my room and cry," says Reddick, who lives with her son and husband. "And I probably couldn't count how many hours a day I cried." Reddick is among the many women who suffer from depression during pregnancy and after childbirth. "There's this kind of myth that women couldn't possibly be depressed during pregnancy, [that] this is such a happy time," says Jennifer Payne, a psychiatrist and the director of the Women's Mood Disorders Center at Johns Hopkins University. "The reality is that a lot of women struggle with anxiety and depression during pregnancy as well as during the postpartum period." An estimated one in seven women experiences depression during or after pregnancy. Among some groups, such as teenage moms and women with a history of trauma, the rate can be even higher. Left untreated, depression during this time can have serious consequences on the health of the mother, the baby and the entire family. © 2020 npr

Keyword: Depression; Sexual Behavior
Link ID: 27005 - Posted: 01.29.2020

A fast acting ketamine-like anti-depressant spray that can lift mood within hours has been rejected by the NHS healthcare watchdog. The National Institute for Health and Care and Excellence (NICE) says there are too many uncertainties about the correlation between the price and clinical benefits of esketamine. It is licensed as a therapy for people with hard-to-treat depression. But it costs about £10,000 per patient for a single course of treatment. Mixed reactions Some people already prescribed it - as part of a trial, for example - will be able to continue on the treatment if their doctor says it is appropriate to do so, the NICE's draft recommendation for England and Wales says. Scotland is yet to issue guidance. Experts have expressed mixed reactions to NICE's decision. Dr Sameer Jauhar, at the Institute of Psychiatry, Psychology and Neuroscience, King's College London, said NICE had made the call because there was not yet enough long-term evidence to support the use of nasal esketamine alongside another anti-depressant. Consultant psychiatrist Dr Paul Keedwell, at Cardiff University, said patients would be disappointed by a decision based largely on cost rather than lack of effectiveness. Marjorie Wallace, chief executive of mental health charity Sane, said: "People with depression are currently relying on medications that are 30 years old. "Although these drugs can be life-saving for some people, they can have unpleasant side-effects and do not work for everyone. "It is therefore deeply disappointing that the first new compound that works in a fundamentally different way on the brain should not have passed this hurdle. "This is especially so because people can take as much as six to eight weeks to feel the full effects of most anti-depressants. "We hope this setback will serve only to inspire pharmaceutical companies, researchers and others to discover new ways of treating serious depression." Recreational misuse Ketamine is used in medicine to numb the body or induce sleep and sometimes prescribed for depression. © 2020 BBC.

Keyword: Depression; Drug Abuse
Link ID: 27004 - Posted: 01.29.2020

By Laura Sanders After taking a compound found in magic mushrooms, people with cancer had less anxiety and depression, even years later, a new study suggests. The evidence isn’t strong enough yet to pin these lasting improvements on the hallucinatory episode itself, as opposed to other life changes. But the findings leave open the possibility that the compound, called psilocybin, may be able to profoundly reshape how people handle distress and fear (SN: 9/26/06). Research published in 2016 suggested that a dose of psilocybin in combination with therapy could quickly ease anxiety and depression in people with cancer. But scientists wanted to know whether these effects lasted. Surveys conducted about three and 4½ years after the psilocybin dose showed that a majority of the 15 people still had fewer signs of anxiety and depression compared with before they took the compound, the team reports January 28 in the Journal of Psychopharmacology. (By the second follow-up, about a third of the participants still had active cancer; the rest were in partial or complete remission.) All the participants said they had “moderate,” “strong” or “extreme” positive changes in their behavior that they attribute to their experience, which many described as one of the most personally meaningful events of their lives. © Society for Science & the Public 2000–2020

Keyword: Depression; Drug Abuse
Link ID: 27003 - Posted: 01.29.2020

Elena Renken The sting of a paper cut or the throb of a dog bite is perceived through the skin, where cells react to mechanical forces and send an electrical message to the brain. These signals were believed to originate in the naked endings of neurons that extend into the skin. But a few months ago, scientists came to the surprising realization that some of the cells essential for sensing this type of pain aren’t neurons at all. It’s a previously overlooked type of specialized glial cell that intertwines with nerve endings to form a mesh in the outer layers of the skin. The information the glial cells send to neurons is what initiates the “ouch”: When researchers stimulated only the glial cells, mice pulled back their paws or guarded them while licking or shaking — responses specific to pain. This discovery is only one of many recent findings showing that glia, the motley collection of cells in the nervous system that aren’t neurons, are far more important than researchers expected. Glia were long presumed to be housekeepers that only nourished, protected and swept up after the neurons, whose more obvious role of channeling electric signals through the brain and body kept them in the spotlight for centuries. But over the last couple of decades, research into glia has increased dramatically. “In the human brain, glial cells are as abundant as neurons are. Yet we know orders of magnitude less about what they do than we know about the neurons,” said Shai Shaham, a professor of cell biology at the Rockefeller University who focuses on glia. As more scientists turn their attention to glia, findings have been piling up to reveal a family of diverse cells that are unexpectedly crucial to vital processes. All Rights Reserved © 2020

Keyword: Glia; Pain & Touch
Link ID: 27002 - Posted: 01.28.2020

Scott Grafton When people ask me about the “mind-body connection,” I typically suggest walking on an icy sidewalk. Skip the yoga, mindfulness, or meditation, and head to the corner on a cold, windy, snowy day. Every winter, much of North America becomes exceedingly slippery with ice. Emergency rooms across the continent see a sharp uptick in fractured limbs and hips as people confidently trudge outside in such conditions, unveiling a profound disconnection between what people believe and what they can actually do with their bodies. One might think that a person could call on experience from years past to adjust their movement or provide a little insight or caution. But the truth is that the body forgets what it takes to stay upright in these perilous conditions. Why is there so much forgetting and relearning on an annual basis? We remember how to ride a bike. Why can’t we remember how to walk on ice? I attempt to answer this and other questions concerning the connection (or lack thereof) between motion in the mind and motion by the body in my new book, Physical Intelligence: The Science of How the Body and the Mind Guide Each Other Through Life. Pantheon, January 2020 Falling on ice reveals a delicate tradeoff that the brain must reconcile as it pilots the body. On the one hand, it needs to build refined motor programs to execute skills such as walking, running, and throwing. On the other hand, those programs can’t be too specific. There is a constant need to tweak motor plans to account for dynamic conditions. When I throw a backpack on, my legs don’t walk in the same way as they do without the pack: my stance widens, my stride shortens. Often, the tweaking needs to happen in moments. As I pick the pack up, I need to lean in or I could tip myself over. Just as importantly, as soon as I put it down, I need to forget I ever held it in the first place. © 1986–2020 The Scientist

Keyword: Learning & Memory
Link ID: 27001 - Posted: 01.28.2020

By Gretchen Vogel A prominent neuroscientist whose German lab was targeted by animal rights activists is heading to China, where he says he will be freer to pursue his work on macaques and other monkeys. Nikos Logothetis, a director at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, told colleagues last week that the first members of his lab would move in the coming months to a new International Center for Primate Brain Research (ICPBR) in Shanghai, which he will co-direct with neuroscientist Poo Mu-Ming, scientific director of the Chinese Academy of Sciences’s Center for Excellence in Brain Science and Intelligence Technology. Logothetis says he will follow as soon as remaining lab members have finished their projects, likely by late 2020 or early 2021. The Chinese institute is building a new facility in Shanghai’s Songjiang district, which will house as many as 6000 nonhuman primates, including many transgenic monkeys. “Scientifically it’s incredible,” he says. “They have excellent groups working with CRISPR and genetic engineering.” And, he adds, the acceptance of nonhuman primate research by authorities and the public in China is much higher than in Europe. They “know that no other brain (besides that of humans themselves) can be a true help in making progress.” The move is another sign that China’s investment in neuroscience research, especially involving primates, is paying off, says Stefan Treue, a neuroscientist and director of the German Primate Center. “China has made incredible progress in an unbelievably short period of time. That is the positive side of a political system that is able to move very quickly,” he says. “The combination of political will and necessary resources mean that they have put together an impressive collection of neuroscientists.” © 2019 American Association for the Advancement of Science.

Keyword: Animal Rights
Link ID: 27000 - Posted: 01.28.2020

By Laura Sanders A cruel twist of genetic fate brought Alzheimer’s disease to a sprawling Colombian family. But thanks to a second twist, one member of the clan, a woman, managed to evade the symptoms for decades. Her escape may hold the key to halting, or even preventing, Alzheimer’s. The inherited version of Alzheimer’s disease erodes people’s memories early, starting around age 40. In this family and others, a mutation in a gene called presenilin 1 eventually leaves its carriers profoundly confused and unable to care for themselves. Locals around the Colombian city of Medellín have a name for the condition: la bobera, or “the foolishness.” The woman in the afflicted family who somehow fended off the disease carried the same mutation that usually guarantees dementia. And her brain was filled with plaques formed by a sticky protein called amyloid. Many scientists view that accumulation as one of the earliest signs of the disease. Yet she stayed sharp until her 70s. Researchers were stumped, until they discovered that the woman also carried another, extremely rare genetic mutation that seemed to be protecting her from the effects of the first one. This second mutation, in a different Alzheimer’s-related gene called APOE, seemed to slow the disease down by decades, says Joseph Arboleda-Velasquez, a cell biologist at Harvard Medical School. “There was this idea of inevitability,” he says. But the woman’s circumstances bring “a different perspective” — one in which amyloid buildup no longer guarantees problems. Arboleda-Velasquez and colleagues reported the details of the woman’s exceptional case November 4 in Nature Medicine, omitting the woman’s name and precise age to protect her privacy. © Society for Science & the Public 2000–2020

Keyword: Alzheimers
Link ID: 26999 - Posted: 01.27.2020

One day, a scientist in Craig Ferris’s lab was scanning the brains of very old rats when he found that one could see, hear, smell, and feel just like the other rats, but it was walking around with basically no brain—and likely had been since birth. This rat, named R222, did have a brain. But its brain, affected by a condition called hydrocephalus, had compressed and collapsed as it filled with fluid, and many of the functions that would ordinarily be carried out in the brain had relocalized to areas that weren’t taken over by fluid. This provided the tools for Ferris, a psychology professor at Northeastern, to investigate how powerful the brain remains, even when tight on space. This, he says, might even influence the ever-present goal of machine learning: How small can you be and still get the job done? Pretty small, it turns out, at least in R222’s case, but this efficient use of space is dependent on the brain’s capacity to reorganize. This ability, known as neuroplasticity, is a widely documented phenomenon, but such an extreme example was rare, says Ferris. In R222’s case, he says, the processing of visual input “was distributed over much of the remaining brain, and the same thing with smell and touch.” What at first the scans suggested to be a brainless rat was actually a rat with a brain that had been pushed out of the way and flattened like a pancake—and kept working. ©2020 Technology Networks

Keyword: Development of the Brain
Link ID: 26998 - Posted: 01.27.2020

By Aimee Cunningham A concussion diagnosis depends upon a careful assessment of symptoms. Now the largest study to date of sports-related concussion points to a potential medical assist when evaluating a college athlete for this injury. Certain proteins in the blood are elevated after a concussion, researchers report online January 24 in JAMA Network Open. That discovery may one day help with distinguishing athletes who have suffered this brain injury from those who haven’t. Researchers took blood samples pre- and post-injury from 264 college athletes who had concussions while playing football, rugby and other contact sports from 2015 to mid-2018. Blood levels for three proteins were higher than they were before the injury occurred, the researchers found. Each of the three proteins can serve as a sign that damage has occurred to a different type of brain cell, says Michael McCrea, a neuropsychologist at the Medical College of Wisconsin in Milwaukee. Glial fibrillary acidic protein is released in response to injury to glial cells, which provide support to nerve cells in the brain. Ubiquitin C-terminal hydrolase-L1 signals that nerve cells have been injured, and tau is a sign of damage to axons, which transmit nerve impulses. These proteins have been evaluated in past research as potential makers of more severe traumatic brain injury. McCrea’s team also measured these proteins in 138 athletes who played contact sports but were not concussed, and in 102 athletes who did not have the injury and played noncontact sports. The protein levels for these two groups remained steady throughout the study. If there had been large variability in the protein levels in non-concussed athletes, McCrea says, that would have undermined the association between the proteins and concussion. © Society for Science & the Public 2000–2020

Keyword: Brain Injury/Concussion
Link ID: 26997 - Posted: 01.27.2020

By Stephen L. Macknik The year 2015 will go down in the annals of vision research history as a watershed moment. in which the internet discovered an entirely new visual phenomenon—a dress that half of the world saw as black/blue and the other half as white/gold. Had it not been for social media and its particular way of framing conversations around shared crowd-sourced images, this peculiar visual puzzle might have remained unknown. The idea that an object could look one color under one set of lighting conditions, and another color under another set of lighting conditions, was not new. What was unique about The Dress was that the same image, under the same exact viewing conditions, looked very different to different people. The color ambiguity only became evident when half of the viewers disagreed with the other half, which is probably why social media was so pivotal in its discovery. Vision scientists went bananas. Was it an artifact of different device screens? Did it have to do with gender, culture, education, or some other categorization of brain and persona? How many people—exactly—saw the image one way or the other? This was a dress that sailed a thousand ships. The vision science field eventually verified that the phenomenon was definitely real and not an artifact of viewing conditions. Though the precise underlying mechanisms remain unknown, even now. Similarly ambiguous color images followed the dress, but a main obstacle to figuring out how and why such effects existed was that all of the images were flukes. They were accidental happy snaps created by internet picture-posters. Scientists could not intentionally create new and carefully controlled examples for deep study in the lab. Until now. © 2020 Scientific American

Keyword: Vision
Link ID: 26996 - Posted: 01.27.2020

By Jane E. Brody My husband and I were psychological opposites. I’ve always seen the glass as half-full; to him it was half-empty. That difference, research findings suggest, is likely why I pursue good health habits with a vengeance while he was far less inclined to follow the health-promoting lifestyle I advocated. I’m no cockeyed optimist, but I’ve long believed that how I eat and exercise, as well as how I view the world, can benefit my mental and physical well-being. An increasing number of recent long-term studies have linked greater optimism to a lower risk of developing cardiovascular disease and other chronic ailments and to fostering “exceptional longevity,” a category one team of researchers used for people who live to 85 and beyond. Admittedly, the relationship between optimism and better health and a longer life is still only a correlation that doesn’t prove cause and effect. But there is also now biological evidence to suggest that optimism can have a direct impact on health, which should encourage both the medical profession and individuals to do more to foster optimism as a potential health benefit. According to Dr. Alan Rozanski, one of the field’s primary researchers, “It’s never too early and it’s never too late to foster optimism. From teenagers to people in their 90s, all have better outcomes if they’re optimistic.” Dr. Rozanski is a cardiologist at Mount Sinai St. Luke’s Hospital in New York who became interested in optimism while working in a cardiac rehabilitation program early in his career. In an interview, he explained, “Many heart-attack patients who had long been sedentary would come into the gym and say ‘I can’t do that!’ But I would put them on the treadmill, start off slowly and gradually build them up. Their attitude improved, they became more confident. One woman in her 70s said her heart attack may have been the best thing that had happened to her because it transformed what she thought she could do.” © 2020 The New York Times Company

Keyword: Emotions; Neuroimmunology
Link ID: 26995 - Posted: 01.27.2020

By Megan Schmidt Scientists say they’ve figured out what causes essential tremor, a common neurological disorder characterized by involuntary, rhythmic trembling that typically occurs in the hands. In a paper published in Science Translational Medicine this week, researchers at National Taiwan University and Columbia University Irving Medical Center discovered that people with essential tremor have abnormal connections among the neurons in their cerebellum, a region in the back of the brain that’s involved in the coordination of voluntary movement. Researchers say people with these abnormalities tend to generate overactive brain waves, or too much electrical activity, in this region of the brain, which is what fuels the tremors. In addition to pinpointing the roots of the disorder, the researchers say their work uncovered some new approaches that could potentially treat and diagnose essential tremor more effectively. Essential tremor is often mistaken for Parkinson’s disease, but there are some key distinctions that set these movement disorders apart. Parkinson’s, which is less common than essential tremor, is caused by the progressive loss of dopamine neurons in the midbrain, a small region of the brain that plays an important role in motor function. Essential tremor, as this new research reveals, is linked to abnormalities in the hindbrain — specifically, the cerebellum. © 2020 Kalmbach Media Co.

Keyword: Movement Disorders
Link ID: 26994 - Posted: 01.25.2020

Children as young as 6 years old who underwent fetal surgery to repair a common birth defect of the spine are more likely to walk independently and have fewer follow-up surgeries, compared to those who had traditional corrective surgery after birth, according to researchers funded by the National Institutes of Health. The study appears in Pediatrics. The procedure corrects myelomeningocele, the most serious form of spina bifida, a condition in which the spinal column fails to close around the spinal cord. With myelomeningocele, the spinal cord protrudes through an opening in the spine and may block the flow of spinal fluid and pull the brain into the base of the skull, a condition known as hindbrain herniation. In 2011, the Management of Myelomeningocele study, funded by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), found that by 12 months of age, children who had fetal surgery required fewer surgical procedures to divert, or shunt, fluid away from the brain. By 30 months, the fetal surgery group was more likely to walk without crutches or other devices. For the current study, NICHD-funded researchers re-evaluated children from the original trial when they were 6 to 10 years old. Of the 161 children who took part in the follow-up study, 79 had been assigned to prenatal surgery and 82 had been assigned to traditional surgery. Children in the prenatal surgery group walked independently more often than those in the traditional surgery group (93% vs. 80%). Those in the prenatal surgery group also had fewer shunt placements for hydrocephalus, or fluid buildup in the brain (49% vs. 85%), and fewer shunt replacements (47% vs. 70%). The group also scored higher on a measure of motor skills. The two groups did not differ significantly in a test measuring communication ability, daily living skills, and social interaction skills.

Keyword: Development of the Brain
Link ID: 26993 - Posted: 01.25.2020

John Henning Schumann As the owner of a yellow lab named Gus, author Maria Goodavage has had many occasions to bathe her pooch when he rolls around in smelly muck at the park. Nevertheless, her appreciation for his keen sense of smell has inspired her write best-selling books about dogs with special assignments in the military and the U.S. Secret Service. Her latest, Doctor Dogs: How Our Best Friends Are Becoming Our Best Medicine, highlights a vast array of special medical tasks that dogs can perform — from the laboratory to the bedside, and everywhere else a dog can tag along and sniff. Canines' incredible olfactory capacity — they can sniff in parts per trillion — primes them to detect disease, and their genius for observing our behavior helps them guide us physically and emotionally. Goodavage spoke with NPR contributor John Henning Schumann, a doctor and host of Public Radio Tulsa's #MedicalMonday about what she has learned about dogs in medicine What led you to look into dogs in medicine? I've been reading and writing about military dogs and Secret Service dogs for many years now, and it was sort of a natural next step. These are dogs on the cutting edge of medicine. They're either working in research or right beside someone to save their life every day. And really, doctor dogs are, for the most part, using their incredible sense of smell to detect diseases. And if they're paired with a person, they bond with that person to tell them something that will save their life. © 2020 npr

Keyword: Chemical Senses (Smell & Taste)
Link ID: 26992 - Posted: 01.25.2020

By Simon Makin Knowing how the human brain develops is critical to understanding how things can go awry in neurodevelopmental disorders, from intellectual disability and epilepsy to schizophrenia and autism. But between the fact that researchers cannot poke around inside growing human brains and the inadequacies of animal models, scientists currently do not fully understand the process. “We know a bit about the early stages because [the situation is] very similar to what happens in rodents,” says psychiatrist Sergiu Paşca of Stanford University. “But everything beyond the second trimester [of pregnancy] and soon after birth is poorly understood.” Enter the invention of brain “organoids”: cells grown in 3-D clusters in the lab and designed to mimic the composition of the organ’s tissue. The technology recently reached the point where specific brain regions can be modelled for sufficiently long periods to allow researchers to study their development. Paşca and his colleagues have now used organoid models of parts of the human forebrain—the seat of higher cognitive abilities such as complex thought, perception and voluntary movement—to peer into how gene activity drives brain development. “The work brings new understanding of how, as the brain is formed, distinct regulatory regions of the genome are used to execute specific tasks—for example, the generation of specific types of neurons,” says neuroscientist Paola Arlotta of Harvard University, who was not involved in the new study. The researchers used their findings to map genes associated with certain disorders to specific cell types at specific stages, giving insight into the origins of conditions such as autism and schizophrenia. © 2020 Scientific American,

Keyword: Development of the Brain
Link ID: 26991 - Posted: 01.25.2020

Abby Olena Understanding the array of neural signals that occur as an organism makes a decision is a challenge. To tackle it, the authors of a study published last week (January 16) in Cell imaged large swaths of the larval zebrafish brain as the animals decided which way to move their tails to avoid an undesirable situation. Finding patterns in the data, they were then able to use imaging to predict—10 seconds in advance—the timing and direction of the fish’s movement. “In a lot of other model systems it’s really difficult to actually . . . record something that’s happening throughout the whole brain with a high level of precision,” says Kristen Severi, a biologist at the New Jersey Institute of Technology who was not involved in the study. “When you have something like a larval zebrafish where you have access to the entire brain with single-cell resolution in a transparent vertebrate, it’s a great place to start to try to look for activity patterns that might be distributed and might be hard to connect.” Even if an animal has learned to do something, it doesn’t execute the exact same motor responses every time, says biophysicist Alipasha Vaziri of the Rockefeller University. He adds that common approaches to studying the neural basis of decision-making may not tell the whole story. For instance, monitoring a handful of neurons and then extrapolating from their activity what’s happening brain-wide means that researchers might miss the big picture. Likewise, recording across the whole brain and then averaging results across trials risks losing details essential to understanding how the brain encodes this behavior. © 1986–2020 The Scientist

Keyword: Brain imaging
Link ID: 26990 - Posted: 01.24.2020

Katarina Zimmer Around 30 years ago, researchers in the UK discovered DNA strands of herpes simplex virus 1 in postmortem brain samples of Alzheimer’s patients at much higher levels than in healthy brains, hinting that viral infection could be somehow involved in the disease. Since then, a string of studies has bolstered the association between Alzheimer’s disease and HSV1, as well as other pathogens, particularly the herpesviruses HHV6A and HHV6B, yet proving causality has remained elusive. Now, in an extensive screen of hundreds of diseased brains from three separate cohorts, a collaboration of US-based researchers reports no evidence for increased RNA or DNA levels of HHV6A or HHV6B in tissue from people with Alzheimer’s disease relative to that from healthy individuals, contradicting the results of some previous results. The scientists also failed to find an association between transcripts of other viruses that have been linked to Alzheimer’s, such as Epstein-Barr virus and cytomegalovirus, and Alzheimer’s, they report today (January 23) in Neuron. “I’m very surprised,” Ruth Itzhaki, an Alzheimer’s disease researcher currently at the University of Oxford who was among those who first associated HSV1, and later HHV6, with the disease, writes to The Scientist in an email. “If their findings are correct, absence of HHV6 would make any involvement in Alzheimer’s disease unlikely,” although not impossible, she notes. Several groups have reported the presence of HHV6 viruses in the brains of Alzheimer’s patients, most notably in a 2018 Neuron study. In that investigation, researchers had found higher levels of HHV6A in patients than in healthy controls, largely based on RNA and DNA sequencing data. © 1986–2020 The Scientist

Keyword: Alzheimers; Neuroimmunology
Link ID: 26989 - Posted: 01.24.2020